1. Field of the Invention
The present invention relates generally to boat or ship stabilizing devices and more particular to a stabilizing apparatus that is adapted to operated when at least one or more stabilizers are suspended over the sides or ends of a vessel so as to dampen the rolling motion of the vessel while the vessel is at anchor, moored, riding at sea-anchor, docked or drifting.
2. Description of the Prior Art
As is well known in the art, various problems and difficulties are encountered in providing suitable means for reducing the roll and/or pitch of floating vessels, such as boats, ships and the like.
Many types of stabilizers have been tried and suggested. However, some of these devices have various design limitations that have proven to operate poorly and inefficiently under working conditions. Moreover, some types of stabilizers are complicated to operate and expensive to maintain. As examples of some known boat stabilizers, one may refer to any of the following United States Patents.
There is disclosed in U.S. Pat. No. 1,299,186 to T. Imaizumi a ship stabilizer which includes a plurality of upright cups suspended from opposite sides of a boat.
U.S. Pat. No. 3,179,078 to J. R. Popkin is directed to a hydrofoil stabilizer for sailboats.
U.S. Pat. No. 3,260,232 to D. W. Douglas discloses a stabilizer suspended from a boat by means of a pair of cables positioned forwardly and rearwardly of the center of gravity of such stabilizer whereby the pitch thereof may be controlled.
U.S. Pat. No. 2,561,539 to Seaward is directed to a marine stabilizer which includes a triangularly shaped fin, which is weighted at its forward extremity by means of a weight. The fin is attached to a pole projecting transversely from a boat by means of a cable. When the boat rolls to one side the weight will cause the fin to plunge downwardly nose first and when the boat rolls to the opposite side, raising the fin, the cable will pull the nose of such fin upwardly causing such fin to assume a horizontal orientation to resist rolling of the boat.
One may also refer to U.S. Pat. No. 3,589,324 which is known in the industry as Roll-Control and consist of a rectangular frame structure covered by a sheet material that is cut in the center thereof to define a flap valve.
Other known stabilzing devices include the ROLL-EEZ which is a rectangular frame member having a plurality of movable vanes mounted therein and the Rocker-Stopper which is a cone-shaped device formed from a lightweight plastic.
Many seasons of cruising have proven the general disappointment with the available devices meant to dampen the rolling motion of vessels on the water, and provided the impetus to design a more efficient device. The problems with the available devices are largely in two areas. The first involves the use of too much energy in the actuation of their valve-flap-door-gait system, limiting their vertical working displacement and causing a curve of increasing efficiency very slowly through time in a resistance or drop mode. That is to say that the prevailing designs offer maximum resistance-to-roll forces for a very brief period of the rolling cycle, and the resistance is further compromised by frictional, buoyant, and actual operational forces by virtue of a poor design concept. Secondly, theses devices provide a flat surface in the resistance phase, and have a tendency in more than above moderate sea conditions to slide horizontally, providing horizontal force components to hinder the vertical water-pressure-based operations.
All devices that reduce rolling use the rocking motion of the vessel to actuate the device. When fastened to the side of a vessel or cantilevered as far outboard as convenient, a roll toward the side from which the device is hanging will lower it in the water column, and a roll back to the other side will raise it in the water column. Thus, the working phase of the cycle occurs with lifting where the shape of the device offers hydrodynamic resistance against the water dragging above it. Conversely, in the downward or dropping portion of the cycle the mass and shape should allow gravity to pull the device to the bottom of a working cycle with minimal resistance. A device which has insufficient mass, or uses excessive working forces to change surface areas, or offers too much surface area in the free-fall stage or too little surface area in the resistance stage, will provide a fraction of its potential dampening action. In addition, a device must change surface areas within a minimum of the vertical displacement to do actual work, or be effective in the moderate rolling that occurs most frequently in more sheltered anchorages.